[Joelib-devel] Re: [QSAR-devel] RE: Qsar-devel digest, Vol 1 #102 - 1 msg

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Hi Oleg,

please give links and references to literature and any further ideas and 
implemtations ... not that this means i will implement all those things 
... but lets discuss them.

As far as i know there is a faster approach using eigenvalues, but i 
have read it is not as general for all kind of weighted adjacency 
matrices, so do you know if this is correct?

Kind regards, Joerg

> "The characteristic polynomial is calculated by using the Le
> Verrier-Faddeev-Frame method, which uses a framework of recursive matrix
> operations." -- this is prety computationaly demanding method I sugest using
> optimizied eigen values calculation algorithm (BLAS for symetric matrices)
> and with the resulting eigenvalues one can easy calculate coeficients of the
> characteristic polynomial.
> 
> Oleg Ursu,
> 
> 
>  
> 
> -----Original Message-----
> From: qsa...@li...
> [mailto:qsa...@li...] On Behalf Of
> qsa...@li...
> Sent: Monday, February 07, 2005 6:27 AM
> To: qsa...@li...
> Subject: Qsar-devel digest, Vol 1 #102 - 1 msg
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> Today's Topics:
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>    1. New JOELib2 release: bug fix + characteristic polynomials (Joerg
> Wegner)
> 
> --__--__--
> 
> Message: 1
> Date: Sun, 6 Feb 2005 15:48:45 +0100 (MET)
> From: Joerg Wegner <we...@in...>
> To: flo...@st...,
> 	fro...@in...,
> 	joelib <joe...@li...>,
> 	joe...@li..., qsa...@li...
> Cc: chr...@un...
> Subject: [QSAR-devel] New JOELib2 release: bug fix + characteristic
> polynomials
> 
> Hi all,
> 
> minor bug fix release (atom label caching indexing for last atom in a
> molecule, for some properties only) and minor feature enhancement
> (characteristic polynomial).
> 
> After looking for a reasonable interpretation for eigenvalues of the
> adjaceny matrix i have found the analogy to the hueckel matrix.This is
> fantastic, but not really general for all weighted adjaceny matrices, with
> user defined atom and bond labels.
> 
> Nontheless there exists still a much better analytical interpretation of the
> (weighted) adjaceny matrix (with atom and bond labels) which is called the
> characteristic polynomial.
> If the polynomials (their coefficients) of two graphs are identical then
> those graphs are isospectral (spectral theory of graphs).
> 
> Using the Heilbronner theorem, we can check and interpret substructural
> fragments, at least on a linear fragment level.
> 
> Heilbronner theorem:
> P(G)=P(G-eij)-P(G-vi-vj)-2*sum(P(G-Z))
> 
> P(G) is the characteristic polynomial in its general form any edge eij
> G-eij: Graph without this edge
> G-vi-vj: Graph without edge atoms
> sum(P(G-Z)): Sum over ALL rings Z, which contains eij. Please note that this
> means really all rings and not only the SSSR ring set, so this is quite
> nice, but hard to be calculated.
> 
> The characteristic polynomial is calculated by using the Le
> Verrier-Faddeev-Frame method, which uses a framework of recursive matrix
> operations.
> 
> Kind regards, Joerg Kurt Wegner
> 
> Dipl. Chem. Joerg K. Wegner
> Center of Bioinformatics Tuebingen (ZBIT) Department of Computer
> Architecture Univ. Tuebingen, Sand 1, D-72076 Tuebingen, Germany
> Phone: (+49/0) 7071 29 78970
> Fax: (+49/0) 7071 29 5091
> E-Mail: mailto:we...@in...
> WWW:    http://www-ra.informatik.uni-tuebingen.de
> --
> Never mistake motion for action.
>                                     (E. Hemingway)
>                          
> Never mistake action for meaningful action.
>                                (Hugo Kubinyi,2004)                         
> 
> 
> 
> 
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-- 
Dipl. Chem. Joerg K. Wegner
Center of Bioinformatics Tuebingen (ZBIT)
Department of Computer Architecture
Univ. Tuebingen, Sand 1, D-72076 Tuebingen, Germany
Phone: (+49/0) 7071 29 78970
Fax: (+49/0) 7071 29 5091
E-Mail: mailto:we...@in...
WWW:    http://www-ra.informatik.uni-tuebingen.de
--
Never mistake motion for action.
                                     (E. Hemingway)

Never mistake action for meaningful action.
                                (Hugo Kubinyi,2004)